title: Desorption of arsenic from exhaust activated carbons used for water purification.
abstract: This work aims to the analysis of arsenic desorption from an exhaust activated carbon used for the purification of a natural water. This last was used to mimic the properties of common groundwater or drinking water. Different low-cost and harmless eluting solutions were considered, including distilled water, natural water, saline (NaCl, CaCl₂ and NaNO₃) and basic (NaOH) solutions. Experimental results showed that, for 1g of activated carbon with arsenic loading close to the maximum value available for the model natural water (ω ≈ 0.1 mg/g), it is possible to recover more than 80% of the arsenic using 20 ml of 0.1 M sodium chloride solution. A temperature variation within 20 and 40 °C has scarce effect on desorption efficiency. A comparison between desorption data and adsorption isotherms data suggests that arsenic adsorption is actually a reversible process. Therefore, it is virtually possible to increase arsenic recovery efficiency close to 100% by increasing the NaCl concentration or the volume of the desorption solution, but a preliminary cost benefit analysis lead to consider a NaCl 0.1M solution as an optimal solution for practical applications.
authors.affiliation: Dipartimento di Ingegneria Chimica, Università di Napoli Federico II, P.le Tecchio, 80-80125 Napoli, Italy. francesco.dinatale@unina.it
authors.forename: F
authors.initials: F
authors.lastname: Di Natale
authors.forename: A
authors.initials: A
authors.lastname: Erto
authors.forename: A
authors.initials: A
authors.lastname: Lancia
mesh_terms: D000042:Absorption; D000327:Adsorption; D001151:Arsenic / Q000032:analysis / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002606:Charcoal / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D011786:Quality Control; D012492:Salts / Q000737:chemistry; D012965:Sodium Chloride / Q000737:chemistry; D012972:Sodium Hydroxide / Q000737:chemistry; D013054:Spectrophotometry, Atomic; D013696:Temperature; D014867:Water; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D012492:Salts; D014874:Water Pollutants, Chemical; D014867:Water; D002606:Charcoal; D012965:Sodium Chloride; D012972:Sodium Hydroxide; D002244:Carbon; D007501:Iron; D001151:Arsenic
keywords: Activated Carbon; Arsenic; Desorption; Natural Water